Analysis of cases of renal pelvis dilatation detected in the renal ultrasonography screening of 1-month-old infants

Abstract

We routinely perform renal ultrasonography screening in all infants who undergo a health checkup at 1 month of age. In the past 11 years, 106 cases of dilation of the central echo complex (CEC) have been reported. We analyzed the correlation between the anteroposterior diameter (APD) of the renal pelvis at the screening and consequences of patients. Considering that the patients whose renal pelvis dilatation had not resolved spontaneously had significantly longer APD (p=0.0457), patients with long APD should be followed up carefully. We also investigated the cutoff APD of the renal pelvis, which predicts cases requiring a detailed and more efficient examination. Although the cutoff APD may be revised adequately from 7.0–8.1 mm, missing cases that should be diagnosed as obstructive urinary tract diseases is a concern. Further study is needed to decide whether the cutoff value should be revised. In the patients whose CEC dilation resolved spontaneously, no correlation was found between the APD at screening and that during spontaneous regression. It may be difficult to predict the time of regression by evaluating the APD of the renal pelvis at screening.